Devices, systems, and methods for in-stent restenosis prediction

ABSTRACT

Intravascular devices, systems, and methods are disclosed. In some instances, a method for treating a vessel of a patient includes collecting intravascular ultrasound imaging data of the placement of the stent using the intravascular ultrasound imaging device, estimating, using a processing device, a restenosis probability value based on the intravascular ultrasound imaging data of the placement of the stent and communicating the estimated restenosis probability value to a clinician. Associated devices and systems are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of the U.S.Provisional Patent Application No. 62/090,251, filed Dec. 10, 2014,which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure is generally related to the assessment ofvessels, and in particular, to the assessment of the severity ofblockage or other restrictions to the flow of fluid through a vessel,the treatment thereof, and the recurrence thereof.

BACKGROUND

Intravascular imaging systems and other intravascular physiologymeasurement systems are widely used in interventional cardiology asdiagnostic tools for a diseased vessel, such as an artery, within thehuman body. Various sensors may be placed on a catheter and positionedin the body. One type of imaging system is an intravascular ultrasound(IVUS) system. In one example, a phased array IVUS device includes anumber of transducers that are passed into a vessel and guided to anarea to be imaged. The transducers emit ultrasonic waves in order tocreate an image of the vessel of interest. The ultrasonic waves arepartially reflected by discontinuities arising from tissue structures(such as the various layers of the vessel wall), red blood cells, andother features of interest. Echoes from the reflected waves are receivedby the transducer and passed along to an IVUS imaging system. Theimaging system processes the received ultrasound echoes to produce across-sectional image of the vessel where the device is placed.

Intravascular imaging systems are often used to detect arterialocclusions that can be relieved through use of a balloon catheter. Aballoon catheter is a type of catheter with a balloon disposed near thetip. The balloon catheter is designed to be inserted into a patient'sartery and positioned to a spot where an occlusion was detected throughuse of an intravascular imaging system. Upon reaching the detectedocclusion, the balloon is inflated to compress the material causing theocclusion. In some instances, the balloon catheter is utilized to deploya stent. In that regard, inflation of the balloon causes the stent toexpand and deploy the stent within the vessel.

In some instances, an imaging system may be used to image the site of astent in effort to observe, based on clinician experience, whether theplacement of the stent is adequate. However, such current approacheshave not been entirely satisfactory. Accordingly, there remains a needfor improved devices, systems, and methods of objectively evaluatingrisk associated with and likelihood of success for one or more availabletreatment options for the vessel.

SUMMARY

The present disclosure provides devices, systems, and methods forassessing and treating an intravascular lesion and for assessing theefficacy of the treatment. As a result, the surgical process andtreatment of the patient are improved by estimating the futureperformance of the treatment, which may be used to perform additionalinterventions right then, rather than in a subsequent medical procedureat a later time. Aspects of the present disclosure may reduce follow-upprocedures and provide improved outcomes for the patients.

One general aspect includes a method of treating a vessel within apatient. The method includes inserting a catheter including a stentplacement assembly and an intravascular ultrasound imaging device into alumen of the vessel, positioning the catheter at a site of a lesionwithin the lumen of the vessel, activating the stent placement assemblyto place the stent at the site of the lesion within the lumen of thevessel, and collecting intravascular ultrasound imaging data of theplacement of the stent at the site of the lesion using the intravascularultrasound imaging device disposed on the catheter. The method furtherincludes estimating a restenosis probability value based on theintravascular ultrasound imaging data of the placement of the stent atthe site of the lesion. The method also includes communicating theestimated restenosis probability value to a clinician.

Implementations may include one or more of the following features. Themethod further includes imaging a lumen of the vessel with the imagingdevice as the catheter is advanced or retracted through the vessel andidentifying and imaging a lesion within the lumen of the vessel with theimaging device. The catheter includes the intravascular imaging deviceon a distal portion of the catheter. The estimating the restenosisprobability value includes estimating the restenosis probability valuebased on at least one of a tissue type at the site, a plaque type at thesite, a type of the stent, or location of the stent within the vessel.

One general aspect includes another method of treating a vessel within apatient. The method includes positioning a catheter at a site of alesion within a lumen of the vessel, the catheter including a stentplacement assembly, activating the stent placement assembly to place thestent at the site of the lesion within the lumen of the vessel, andestimating a restenosis probability value based on the placement of thestent at the site of the lesion.

Another general aspect includes a medical diagnosis and treatmentsystem. The system includes a non-transitory, computer-readable mediumto store instructions thereon and a processing device, in communicationwith the medium. The processing device executes the instructions toperform operations including receiving imaging data obtained by animaging device on a catheter at a placement site of a stent within alumen of a vessel of a patient and estimating a restenosis probabilityvalue based on the placement of the stent at the placement site, theplacement site corresponding to a location of a lesion of the vessel.Some implementations of these aspects include corresponding computersystems, apparatus, and computer programs recorded on one or morecomputer storage devices coupled to one or more processing devices, eachconfigured to perform or implement the actions of the methods.

Additional aspects, features, and advantages of the present disclosurewill become apparent from the following detailed description.

BRIEF DESCRIPTIONS OF THE DRAWINGS

Illustrative embodiments of the present disclosure will be describedwith reference to the accompanying drawings, of which:

FIG. 1 is a diagrammatic view of a medical system for treating a vesselof a patient according to some embodiments of the present disclosure.

FIGS. 2A, 2B, 2C, 2D, 2E, and 2F are diagrams showing an illustrativeinsertion of a catheter into a vessel of a patient, according toembodiments of the present disclosure.

FIG. 3 is a diagrammatic, partially cross-sectional view of an imagingcatheter device, according to some embodiments of the presentdisclosure.

FIG. 4 is a perspective view of the imaging catheter device of FIG. 3showing the stent thereon, according to embodiments of the presentdisclosure.

FIG. 5 is a visual depiction of a user interface provided by a medicalsystem, according to some embodiments of the present disclosure.

FIGS. 6, 7, and 8 are flow diagrams of methods of treating a vessel ofthe patient, according to some aspects of the present disclosure.

These accompanying drawings will be better understood by reference tothe detailed description that follows.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It is nevertheless understood that no limitation tothe scope of the disclosure is intended. Any alterations and furthermodifications to the described devices, systems, and methods, and anyfurther application of the principles of the present disclosure arefully contemplated and included within the present disclosure as wouldnormally occur to one skilled in the art to which the disclosurerelates. In particular, it is fully contemplated that the features,components, and/or steps described with respect to one embodiment may becombined with the features, components, and/or steps described withrespect to other embodiments of the present disclosure. For the sake ofbrevity, however, the numerous iterations of these combinations will notbe described separately.

Referring now to FIG. 1, shown therein is a schematic diagram depictinga medical system 100. In general, the medical diagnosis and treatmentsystem 100 or, simply, the medical system 100 provides for coherentacquisition, integration, and consolidation of multiple forms ofacquisition and processing elements designed to be sensitive to avariety of modalities used to acquire and interpret human biological,physiology, and morphological information and to coordinate treatment ofvarious conditions. In one embodiment, the medical system 100 includes aprocessing system 101 that is a computer system with the hardware andsoftware to acquire, process, and display medical data and to facilitatecontrol of one or more medical devices, such as intravascular devices.The processing system 101 may be a computer workstation that includes atleast one processing device. Such as a micro controller or the depictedcentral processing unit (CPU) 104 and a non-transitory,computer-readable storage medium (illustrated as memory 106) such as ahard drive, random access-memory (RAM), flash memory, and/or compactdisk read-only-memory (CD-ROM or DVD-ROM), etc. The processing system101 may further include an acquisition card 108 to receive and/orprocess data from multiple medical device modalities. The acquisitioncard 108 may also provide an interface to communicate commands andrequests to coupled medical devices. The memory 106 may include morethan one memory or data storage device and may store data 110 acquiredfrom coupled medical devices and instructions 112. The instructions 112may include executable code that, when executed by the CPU 104 enables auser to view and interact with data received from coupled medicaldevices and/or data stored remotely and that enables a user to controlthe coupled medical devices. The instructions 112 include executablecode to direct the processing system 101 to estimate a restenosisprobability value based on information collected at the site of alesion. In some embodiments, the instructions 112 include executablecode to direct the medical system 100 to perform methods 600 and 700,800 as described in detail further below. The processing system 101 mayalso include video controller such as a graphics processing unit (GPU),a speaker, and a network communication device such as an Ethernetcontroller or wireless communication controller.

In some embodiments, the processing system 101 is programmed to executesteps associated with the medical data acquisition, analysis,estimation, and control described herein. Accordingly, it is understoodthat any steps related to data acquisition, data processing, estimationsbased on acquired data, instrument control, and/or other processing orcontrol aspects of the present disclosure may be implemented by theprocessing system 101 using corresponding instructions stored on or in anon-transitory, computer-readable medium accessible by the processingsystem.

In the depicted embodiment, the medical system 100 is deployed in acatheter lab having a control room, with the processing system 101 beinglocated in the control room. In other embodiments, the processing system101 may be located elsewhere, such as inside the catheter lab, in acentralized area in a medical facility, or at an off-site locationaccessible by an extended network. The catheter lab and control room maybe used to perform on a patient any number of medical sensing andtreatment procedures known in the art. A patient 103, depicted incatheter lab, may be undergoing a single modality or a multi-modalityprocedure either as a single procedure or in combination with one ormore sensing procedures. For example, an angioplasty procedure may beperformed to position a stent in a target location in a target region ofthe vasculature of the patient 103 having a lesion. The patient may beundergoing a percutaneous coronary intervention, performed by aclinician employing the processing system 101.

In the illustrated embodiment of FIG. 1, intravascular device 114 is amedical imaging device that may be utilized by a clinician to acquiremedical imaging data about the patient 103 and/or to provide a treatmentto the patient 103. For instance, the intravascular device 114 mayobtain imaging data (including still images, video, etc.) by usingultrasound (e.g., IVUS), OCT, thermal, and/or other imaging techniques.The intravascular device 114 may be any form of device, instrument,catheter, guidewire, or probe that is sized and shaped to be positionedwithin a vessel. In some embodiments, intravascular device 114 may becombined with a non-imaging component into a single package that issized and shaped to be positioned within a vessel. As illustrated, theIVUS intravascular device 114 is an IVUS catheter that includes one ormore sensors such as a phased-array transducer to collect IVUS sensingdata. In some embodiments, the intravascular device 114 may be capableof multi-modality sensing such as both IVUS and intravascularphotoacoustic (IVPA) imaging, OCT imaging, pressure sensing, and flowsensing, etc.

In the depicted embodiment, a patient interface module (PIM) 116 couplesthe intravascular device 114 to the medical system 100. The PIM 116facilitates the exchange of information between the intravascular device114 and the processing system 101, serving as a medical device interfacetherebetween. The acquisition card 108 may provide communication betweenthe CPU 104 and the intravascular device 114 by exchanging informationwith the PIM 116. This information includes imaging data transmittedfrom the intravascular device 114 to the processing system 101 andcommands and settings, which may include individual parameterspecifications, communicated from the processing system 101 to the PIM116 and to the intravascular device 114 itself. Thus, the PIM 116 isoperable to receive medical imaging and/or sensing data collected fromthe patient 103 using the intravascular device 114 and to transmit thereceived data to a processing system such as the processing system 101.

A bedside controller 118 is also communicatively coupled to theprocessing system 101 and provides user control of the particularmedical modality (or modalities) being used to diagnose and/or treat thepatient 103. In the current embodiment, the bedside controller 118 is atouch screen controller that provides user controls and diagnosticimages on a single surface within the field of operation. In alternativeembodiments, however, the bedside controller 118 may include both anon-interactive display and separate controls 120 such as physicalbuttons and/or a joystick, and/or a keyboard and mouse. In theintegrated medical system 100, the bedside controller 118 is operable topresent control options for the intravascular device 114 and patientimaging data collected therefrom in graphical user interfaces (GUIs).

The medical system 100 provides a medical imaging system interface bywhich a stent may be observed after deployment of the stent to monitorthe success of the deployment, thereby avoiding underdeployment of thestent, and by which an estimate or prediction of a probability ofrestenosis may be communicated to the clinician. More detail regardingthe estimation of a restenosis probability is provided herein.

FIGS. 2A-2F are a series of cross-sectional views that illustrate theinsertion and use of therapeutic and imaging catheter(s) into a patient.In some embodiments, the catheter 200 is an integrated catheter,including both imaging and therapeutic capabilities. In otherembodiments, separate catheters or devices are utilized for treatmentand imaging. In such embodiments, the therapeutic treatment is performedusing a first catheter is positioned within the illustrated vessel, andthe imaging is performed using a separate catheter having imagingcapabilities. Additionally, in some embodiments the catheter 200 mayinclude multiple therapeutic modes. For example, the catheter 200 may beconfigured to include a balloon assembly for stent deployment, toprovide for lesion ablation, and gather images of the site, and mayinclude specialized structures and transducers to provide these andother features.

As illustrated in FIGS. 2A-2F, the catheter 200 includes a balloonassembly 202 and an imaging device 203 being sized and shaped for usewithin a vessel 210 of the patient 103 of FIG. 1. In some embodiments,the vessel 210 may be an artery. As illustrated, the catheter 200includes an inner sleeve 204. In some embodiments, the inner sleeve 204has high pressure capability greater than 20 ATM, which makes theballoon assembly 202 suitable for non-compliant post dilatation. Forexample, FIGS. 2A-2F illustrate the use of the catheter 200 to access anintravascular lesion 206, assess the intravascular lesion 206, and treatthe intravascular lesion 206 using a treatment device, such as anexpandable stent 208, according to one embodiment of the presentdisclosure. The catheter 200 is also used to assess the placement of theexpandable stent 208 within the vessel 210. The assessment of theplacement of the expandable stent 208 may be performed by collectingimaging data and other data (e.g., pressure, flow, etc.) both before andafter the placement of the stent 208. Such data may include informationdescribing a tissue type at the site, a plaque type at the site, a typeof the stent, and/or the location of the stent and lesion within thevessel. For example, the tissue type(s) and plaque type(s) at the sitemay be collected by imaging with the imaging device 203 using a virtualhistology approach, such as those described in one or more of U.S. Pat.No. 6,200,268 titled “VASCULAR PLAQUE CHARACTERIZATION,” U.S. Pat. No.6,381,350 titled “INTRAVASCULAR ULTRASONIC ANALYSIS USING ACTIVE CONTOURMETHOD AND SYSTEM,” U.S. Pat. No. 7,074,188 titled “SYSTEM AND METHOD OFCHARACTERIZING VASCULAR TISSUE,” U.S. Pat. No. 7,175,597 titled“NON-INVASIVE TISSUE CHARACTERIZATION SYSTEM AND METHOD,” U.S. Pat. No.7,215,802 titled “SYSTEM AND METHOD FOR VASCULAR BORDER DETECTION,” U.S.Pat. No. 7,359,554 titled “SYSTEM AND METHOD FOR IDENTIFYING A VASCULARBORDER,” and/or U.S. Pat. No. 7,463,759 titled “SYSTEM AND METHOD FORVASCULAR BORDER DETECTION,” each of which is hereby incorporated byreference herein in its entirety.

In the pictured embodiment, the treatment device comprises balloonassembly 202 the expandable stent 208. In other embodiments, the stent208 may comprise any of a variety of expandable devices shaped andconfigured to be carried on the balloon assembly 202 or another part ofthe catheter for the treatment intravascular lesions. Further, thecatheter 200 may be configured to deploy other treatments. For example,the treatment device may comprise a scaffolding device, a valve device,a filtering device, a stent graft, an ablation device, a drug deliveryor an elution device. In some instances, the treatment device may bedesigned to indefinitely remain in the vessel after removable of thecatheter 200. In other instances, the treatment device may be designedfor removal along with the catheter 200 or removal at a later time.

FIG. 2A illustrates the catheter 200 being advanced into a patient'svessel 210. Initially, a guidewire 212 is fed into the vessel 210. Inone aspect, a guidewire 212 having a diameter of approximately 0.014inches can be utilized. The catheter 200 can then be moved along theguide-wire 212 deeper into the patient's vessel 210. During insertion ofthe catheter 200 into the vessel 210, the balloon assembly 202 is notinflated and maintains a low profile in an unexpanded condition. Adistal end 214 of the catheter 200 can be designed to facilitate entryand progress through the vessel 210. For example, the distal end 214 maybe tapered.

As shown in FIG. 2A, the catheter 200 is pushed into the vessel 210until the imaging device 203 and a distal junction 216 of the balloonassembly 202 enters the vessel 210. The catheter 200 is then pushedfurther into the vessel 210 until a proximal junction 218 of the balloonassembly 202 enters the vessel 210. Thereafter, the catheter 200 ispushed further into the vessel 210, guided along by a guidewire 212,with a proximal shaft 220 of the catheter 200 extending outside thevessel 210 and outside the patient.

FIG. 2B illustrates the catheter 200 moving through the lesion 206 inthe patient's vessel 210. The imaging device 203 can be used to detectand assess the lesion 206 to facilitate placement of the stent 208. Thelesion 206 includes a proximal end 225 and a distal end 230 and has alength L1 extending from the proximal end 225 to the distal end 230 ofthe lesion 206. As the catheter 200 traverses the vessel 210, aclinician can view the data obtained by the imaging device 203 to assessthe health of the vessel. The imaging data may also relay other vascularcharacteristics, such as, by way of non-limiting example, the pathand/or tortuosity of the vessel 210, information regarding the locationof the lesion 206 within the vessel 210, the regularity or irregularityof the vessel walls within the vessel 210, and various characteristicsabout the blood flow within the vessel 210. The imaging data may beprocessed by the processing system 101 of FIG. 1 to identify the typesof tissue and/or plaque present at the site of the lesion 206. Uponvisualizing the lesion 206, the catheter 200 is advanced further intothe vessel 210 until the balloon assembly 202 is aligned with theocclusion 206. The imaging device 203 can continue to image the vesselas the distal end 214 of the catheter 200 travels through the lesion206, thereby providing the clinician with an accurate assessment of thelocation of the balloon assembly 202. In particular, the imaging device203 is positioned a known distance D1 from the balloon assembly 202,which allows a clinician to advance and/or retract the catheter 200 theknown distance to position the balloon assembly 202 relative to whateverportion of the vessel 210 the imaging device 203 is imaging at a giventime.

The imaging device 203 can also be used to facilitate placement of theballoon assembly 202 relative to the lesion 206. In the illustratedexample, the lesion 206 is an intravascular occlusion that may requirereduction and stenting as a treatment option. As shown in FIGS. 2B and2C, as the imaging device 203 travels through the lesion, the imagingdata relayed by the imaging device 203 can provide information ofvarious anatomic characteristics within the vessel 210, such as, by wayof non-limiting example, the length L1 of the lesion 206, the luminalcontours and cross-sections of the lesion 206 (e.g., the intraluminaldiameter of the vessel 210 proximal, adjacent, and distal to the lesion206), and characteristics of the blood flow through the lesion 206, etc.Using this imaging data, the clinician can advance the catheter 200 anappropriate distance forward to accurately position the unexpandedballoon assembly 202 and overlying stent 208 within the lesion 206. Thestent 208 includes a length L2 extending from a proximal stent end 235to a distal stent end 240. The clinician can assess whether the lengthL2 of the stent is appropriate to treat the lesion 206, which has thelength L1. If the stent 208 is comparatively too short or too long toappropriately treat the lesion 206, the catheter 200 may be removed anda correctly-sized stent may be provided, thereby avoiding the potentialstent failure, collapse, ineffective treatment, or less effectivetreatment that may result from implantation of an inappropriately-sizedstent.

FIG. 2C illustrates the expansion of the balloon assembly 202 and thestent 208 within the lesion 206 in the patient's vessel 210. After theclinician advances the balloon assembly 202 and the stent 208 (in anunexpanded condition) appropriately within the lesion 206, the clinicianmay inflate the balloon assembly 202 by introducing a pressure thereinto both compress the plaque or other material causing the lesion 206 andexpand the stent 208 to maintain the new patency of the vessel 210 atthe location of the lesion 206. As mentioned above, this may be done bypumping an inflation fluid through an inner lumen of the proximal shaft220 of the catheter 200. As the balloon assembly 202 is inflated under apressure, typically in the range of 15-25 ATM, the stent 208 assumes anexpanded condition and compresses the material of the lesion 206 againstinner walls of the vessel 210.

FIG. 2D illustrates the withdrawal of the balloon assembly 202 from thelesion 206 after initial deployment of the stent 208 within the lesion206. The clinician may deflate the balloon assembly 202 and retract orpull back the catheter 200 until the imaging device 203 is positionedproximal to the stent 208. The clinician or a processing system canaccess and use imaging data received by the imaging device 203 as it ispulled back through the deployed stent 208. This imaging data may bereferred to as pullback imaging data. The imaging data may be used toassess the expansion and deployment of the stent 208. In particular, theimaging data allows the clinician to assess appropriate stent appositionagainst the lesion 206 and the arterial wall.

The pullback imaging data and other data may be processed by theprocessing system 101 to estimate a probability of restenosis. Theprocessing system 101 may estimate the restenosis probability based onthe deployment of the stent 208 (such as amount of deployment of thestent 208 relative to the diameter of the vessel on either side of thelesion 206), a tissue type or types present at the site of the lesion206, the type of stent, and the location of the stent 208 within thevessel 210. In some embodiments, the degree of deployment of the stent208 may be determined as a percentage of the pre-deployment diameter ofthe vessel 210 at the site of the lesion 206, as a percentage of atarget or desired deployment diameter, or as a percentage of a diameteror average diameter of the vessel 210 on either side of the lesion 206,or as a percentage of the cross-sectional areas before and after thedeployment of the stent 208.

For example, when the degree of deployment of the stent 208 is indicatedfrom the pullback imaging data as being less than a threshold value, theprocessing system 101 may determine objectively that there is a highprobability of restenosis. This restenosis probability value may becommunicated to a clinician in a variety of ways. In some embodiments, avisual indication of the restenosis probability value may be displayedon the bedside controller 118 or the display 122 of FIG. 1. Thethreshold value may be 60%, 75%, 80%, 95%, or another percentage. Whilethis example estimates the restenosis probability value based on thedegree of deployment, in many embodiments, multiple factors are includedto estimate or calculate the restenosis probability value.

Occasionally, as shown in FIG. 2D, the expansion of the stent 208 isinsufficient to adequately treat the lesion 206. In some procedures, theexpansion of the stent 208 may appear to be sufficient to treat thelesion 206 based on angiography imaging or pressure analysis, but is notactually sufficient or is not likely to be maintained in the future. Forexample, pressure measurements taken proximally and distally to thestent 208 after deployment of the stent 208 may indicate a satisfactorylevel of improvement in the flow through the vessel 210 at the currenttime. However, the collected imaging data of the site of the stent 208may indicate a high probability of restenosis. For example, if a portionof the stent 208 is not positioned against the wall of the vessel 210,this portion may become a favorable site for plaque deposits in thefuture. Accordingly, even when pressure measurements indicate that theperformance of the stent 208 is satisfactory, imaging data obtained by apullback of the catheter 200 may provide additional information inassessing the performance, both now and in the future, of the stent 208.

In FIG. 2D, the stent 208 has not fully expanded to compress the lesion206 against luminal walls 245 of the vessel 210. Instead, the lesion 206remains partially intact and capable of at least partially occludingflow through the vessel 210. The imaging device 203 can convey thisinformation via imaging data to the clinician and the processing system101 may estimate the restenosis probability value and communicate itvisually and/or by audio to the clinician. For example, when theprocessing system 101 estimates the restenosis probability value of thestent 208, which is not fully expanded as shown in FIG. 2D, is above athreshold value the processing system may cause a beep or chime to beproduced on a speaker coupled to the processing system 101. Additionallyor alternatively, the processing system 101 may cause a notification tobe displayed to the clinician. The notification or alert, such as avisual notification or audio notification, associated with the estimatedrestenosis probability value may indicate to the clinician that thestent 208 is not positioned satisfactorily and that ameliorativemeasures should be considered. These ameliorative measures may includeperforming corrections to the deployment of the stent 208 or performingan alternative procedure, such as an ablation procedure to removematerial from the site of the lesion 206. In some embodiments, theprocessing system 101 may generate a recommended intervention (e.g., ahigher pressure deployment of the stent 208, an ablation process, or acombination thereof, etc.) and communicate the recommendation to theclinician in a user interface provided by the processing system 101.

FIG. 2E illustrates the reinsertion and re-expansion of the balloonassembly 202 within the lesion 206 to improve the deployment of thestent 208. The placement of the stent 208 may be assessed again, and ifthe restenosis probability value is still above a threshold additionalsteps may be taken. After the estimation of the restenosis probabilityvalue, if the clinician desires to increase the expansion of the stent208 and further decrease the profile of the lesion 206, the clinicianmay re-advance the catheter 200 and re-position the balloon assemblywithin the stent 208 and the lesion 206. As shown in FIG. 2E, theballoon assembly 202 may be re-inflated at a higher pressure to furtherexpand the stent 208, thereby improving the stent apposition and/orexpansion against the luminal walls 245 of the vessel 210.

FIG. 2F illustrates the withdrawal of the balloon assembly 202 from thelesion 206 after the secondary expansion of the stent 208 within thelesion 206. The clinician may once again deflate the balloon assembly202 and retract the catheter 200 until the imaging device 203 ispositioned proximal to the stent 208. The processing system 101 mayagain use the imaging data obtained by the imaging device 203 during thepullback to assess the expansion and deployment of the stent 208 toestimate another restenosis probability value based on the newconditions. The estimated restenosis probability value may provide anindication to the clinician that there is appropriate stent appositionagainst the lesion 206 and expansion within the vessel 210 and that thefuture performance of the stent 208 is likely to continue withoutrestenosis. If the estimated restenosis probability is below a thresholdvalue, the processing system 101 may indicate the appropriate deploymentof the stent 208 (i.e., appropriate positioning, expansion, andapposition) to the clinician. Then, the clinician may withdraw thecatheter 200 from the vessel 210 (and the patient's body). In someembodiments, the processing system 101 may indicate that the deploymentof the stent 208 is satisfactory. Similarly, the processing system 101may simply not provide an indication that the deployment of the stent208 is unsatisfactory.

FIG. 3 illustrates a device 300 including an imaging catheter forimaging a vessel via intravascular ultrasound (IVUS) while using aballoon 302. The imaging catheter device 300 may be used as describedabove in connection with the catheter 200 in FIGS. 2A-F. The imagingcatheter device 300 includes an imaging assembly 304 configured withinthe balloon 302. Preferably, imaging assembly 304 includes anytechnology suitable for intravascular imaging such as technologies basedon sound, light, or other media. The catheter 300 may include an imagingportion 306 (e.g., with conductor wires extending therethrough,surrounding an inflation lumen, guidewire lumen, or both, and extends todistal tip 308.

As mentioned previously, in some embodiments, the imaging assembly 304is an IVUS imaging assembly. The imaging assembly can be a phased arrayIVUS imaging assembly or a rotational IVUS imaging assembly. In someembodiments, an IVUS array is configured to image beyond the distal endof the catheter, i.e., forward-looking IVUS. In other embodiments, theimaging assembly 304 may use optical coherence tomography (OCT). OCT isa medical imaging methodology using a miniaturized near infraredlight-emitting probe, and is capable of acquiring micrometer-resolution,three-dimensional images from within optical scattering media (e.g.,biological tissue).

The imaging catheter device 300 includes a catheter 310 with an extendedbody terminating at a distal tip 308. The catheter 310 may have one ormore lumens therein such as, for example, a guidewire lumen to allow thecatheter 310 of the device 300 to be guided to a treatment site. Thecatheter 310 may include a separate inflation lumen allowing fluid 312(e.g., air) to be delivered to, and to inflate, balloon 302. Thecatheter 310 may also include the imaging device 304. In FIG. 3, theimaging device 304 is depicted as being located within balloon 302. Aportion 306 of catheter 310 carries requisite hardware for imagingassembly 304 such as conductors or optical fibers. Imaging assembly 304may operate via any suitable imaging modality including, for example,ultrasound, opto-acoustic imaging, OCT, or others. The imaging catheterdevice 300 may be used as generally described above in connection withFIGS. 2A-F. However, the imaging catheter device 300 may be used toobtain at least some imaging data while the balloon 302 is beingdeployed to place a stent at the site of a lesion.

FIG. 4 illustrates the imaging catheter device 300 of FIG. 3 with astent 400 being deployed by the expansion of the balloon 302. As shownin FIG. 4, imaging data is collected based on the reflected signalsproduced by sound waves 402 emitted from the imaging assembly 304 whilethe balloon 302 is expanding to place the stent 400. Accordingly, insome embodiments, collecting imaging data from the site of a lesion maybe performed before, after, and during deployment of a stent or othertreatment. This imaging data may be processed by the processing system101 to identify tissues and plaque at the site and to characterize thesite and/or lesion in terms of physical dimensions. Further, theprocessing system 101 may estimate a restenosis probability duringplacement of the stent 400. The processing system 101 may provide anindication of the restenosis probability value to a clinician duringplacement of the stent 400. In some embodiments, the restenosisprobability value calculated during deployment of the stent 400 may becommunicated as being a preliminary restenosis value. In someembodiments, the restenosis probability value may be estimatedrepeatedly during deployment of the stent 400, such that when therestenosis probability value falls below a threshold value, anindication is provided to a clinician through a user interface toindicate that the probability of restenosis is acceptably small.

FIG. 5 depicts a user interface 500, according to an embodiment of thepresent disclosure, that may be provided by the processing system 101for display by the bedside controller 118 and/or the display 122 ofFIG. 1. The user interface 500 may also be referred to as a screendisplay. The user interface 500 may include multiple tabs or beaccessible as a tab within an overall user interface associated with theprocessing system 101 and or the intravascular device 114 of the medicalsystem 100 illustrated in FIG. 1. The user interface 500 may include aclose-up window 502 that displays a portion of the imaging data 504obtained from a site of a stent placement. When rendered in the close-upwindow 502 in a display, the imaging data 504 includes a depiction ofthe stent 506 within the vessel. The stent 506 is at least partiallydeployed. The displayed portion of imaging data 504 may show the stent506 in a nearly cross-sectional view. The close-up window 502 may enablea clinician to visualize the placement of a stent, such as the stent 208or 400 of FIGS. 2A-F and 4, respectively. The clinician may also be ableto see the cross-sectional configuration of the vessel at the site ofthe stent 506. Vessels may deviate from a generally circularcross-section to varying degrees that may not be observed externally,but may be observed using intravascular imaging devices.

The user interface 500 may also include a full view window 508 that maydisplay the full current view of the rendered imaging data 504. In someembodiments, the windows 502 and 508 may include “live” imaging data. Inother embodiments, one or both of the windows 502 and 508 may displaynon-live or recorded imaging data. In some embodiments, different modesof images may be displayed in the windows 502 and 508. For example,imaging data obtained in a manner to optimize the depiction of plaquemay be shown in the window 502, while imaging data obtained in manner tooptimize the depiction of tissue may be shown in the window 508. Theimaging data may be obtained by alternating between imaging modes. Theimaging modes may be provided by processing a single set of imaging datain different ways or the modes may be provided by alternating betweensettings and parameters implemented by the imaging device within thecatheter to best capture certain features at the imaging site. Forexample, the imaging techniques described in U.S. Provisional PatentApplication No. 61/903,764, filed Nov. 13, 2013 and titled “VisuallyOptimized Intravascular Imaging and Associated Devices, Systems, andMethods,” which is hereby incorporated by reference in its entirety, maybe utilized. Using the visuals provided by the user interface 500, aclinician may apply subjective judgment, based on experience, to assessthe quality of the placement of the stent.

The user interface 500 further includes a stent placement informationwindow 510. The stent window 510 may be used to communicate objectiveinformation regarding the placement of a stent within a patient'svessel. The information recording the placement of the stent is based onphysiological measurements taken by sensors within the vessel, such asintravascular imaging data. The clinician may interact with the userinterface 500 to enable or disable the estimation of the probability ofrestenosis. As shown in FIG. 5, the window 510 include an auto button512A by which the user of the user interface 500, e.g., a clinician, mayaffirmatively request that an estimated restenosis probability value isautomatically and continuously calculated by the processing system 101as physiological data becomes available. The physiological data maybecome available by being collected using a catheter, such as an IVUSimaging catheter, and/or by being accessed from a memory, such as anetworked storage device having physiological data stored thereon. Themanual button 512B may be selected to limit the estimation process. Uponselecting the manual button 512B, a manual mode is activated, in whichan estimated restenosis probability value is calculated when the updatebutton 512C is selected by the clinician. Buttons 512A-C may be selectedby clicking a mouse, entering an associated keystroke on a keyboard,and/or by touching a touch-screen.

The stent placement information window 510 includes an estimatedrestenosis probability area 514 that may display an indication of a mostcurrent estimated restenosis probability value 516. The estimatedrestenosis probability value 516 may be communicated through the userinterface 500 in a variety of ways, only some of which are describedherein. For example, the restenosis probability value 516 may beprovided as a numerical value. In other embodiments, a qualitativedescription of the quantitative, estimated restenosis probability value516 may be provided by applying a plurality of value brackets. Forexample, when the estimated restenosis probability value is between afirst bracket-defining value and a second bracket-defining value, aqualitative description of that bracket may be provided in the estimatedrestenosis probability value area 514, such as “poor,” “fair,” “good,”or “excellent.” In this way, the processing system 101 may communicatequalitative descriptions of the estimated restenosis probability valuethat may be more easily interpreted by the clinician than the actualestimated restenosis probability value itself. In some embodiments, acolor may be displayed to indicate the bracket in which a most recentestimated restenosis probability value belongs, e.g., “red,” “yellow,”or “green.” In other embodiments, the user interface 500 may includeaudio cues to indicate an estimated restenosis probability value. Forexample, the user interface 500 may cause an alert or a beep to begenerated through a speaker whenever the most recent estimatedrestenosis probability value is above a threshold value. Regardless ofthe manner in which the estimated restenosis probability value 516 iscommunicated to a user of the user interface 500, the estimatedrestenosis probability value 516 may communicate that the currentplacement of a stent may not be providing adequate compensation for alesion and/or may not provide adequate compensation for the lesion inthe future. The estimated restenosis probability value 516 may indicatethat, although flow through the stent is improved after initialplacement, the benefits of the stent may not last unless additionalsteps are taken.

The stent placement information window 516 also includes a recommendedintervention area 518, in some embodiments. In embodiments in which aparticular intervention may be determined by the processing system 101to best improve the performance of a stent, the determined means ofachieving that improvement may be displayed for communication in theuser interface 500. As shown in FIG. 5, the processing system 101 hasdetermined that the estimated restenosis probability value is above athreshold value and that redeploying the stent by re-expanding a balloonat a distal portion of the catheter using an increased pressure mayimprove the performance of the stent in the future. As illustrated inuser interface 500, the processing system 101 indicates that an ablationtreatment is not recommended. In some embodiments more than oneintervention may be displayed to a user with accompanying indications ofwhether the intervention is likely to improve the performance of thestent in the future. In other embodiments, a single recommendedintervention may be displayed in the recommended intervention area 518.The user interface 500 may include further buttons or user interfaceelements to enable a clinician to program threshold values that may beused with the estimated restenosis probability value to customize theindications of stent placement performance.

Referring now to FIG. 6, illustrated therein is a flowchart of a method600 of treating a vessel within a patient. For example, the method 600illustrates a method for treating a vessel of the patient 103 of FIG. 1using the medical system 100. The method 600 is illustrated as aplurality of enumerated steps or operations. Embodiments of the method600 may include additional steps or operations before, after, inbetween, or as part of the enumerated steps. The steps of the method 600may be performed using hardware such as the intravascular device 114,the processing system 101 including the CPU 104, and the display 122 ordisplay of the bedside controller 118. In some embodiments, theinstructions for performing some or all of the operations of the method600 may be stored as executable code on a non-transitory computerreadable medium such as the memory 106 of FIG. 1.

The steps of method 600 in FIG. 6: a catheter is inserted into a lumenof the vessel (step 601); collect intravascular ultrasound imaging dataof the placement of the stent at the site of the lesion using theintravascular ultrasound imaging device disposed on the catheter (step602); estimate, using a processing device, a restenosis probabilityvalue based on the intravascular ultrasound imaging data of theplacement of the stent at the site of the lesion (step 604); communicatean indication of the estimated restenosis probability value to aclinician (step 606).

As illustrated in FIG. 6, embodiments of the method 600 may include step604, in which a processing device such as the CPU 104 of the processingsystem 101 estimates a restenosis probability value based on theintravascular ultra sound imaging data of the placement of the stent atthe site of the lesion. Many algorithms may be used to process thecollected imaging data obtained at the site of the lesion and otherinformation to generate an objective measure of restenosis probability.The processing device may estimate the restenosis probability valuebased on tissue types at the site, plaque types at the site and/orplaque presence and geometry, a type of the stent, and/or the locationof the stent within the vessel, the presence of gaps between the stentand the walls of the vessel, the cross-sectional area through the stent(including the shape and/or size of the area and the uniformity of thecross-sectional area through the stent), whether the lesion extendsbeyond the stent, etc. In some embodiments, the processing device mayestimate the restenosis probability value based on the degree ofcurvature in the vessel in areas proximal to the stent. Additionally, insome embodiments in which data other than imaging data is used toprovide information regarding the performance of the stent, theestimation of the restenosis probability value may be based onphysiology measurements such as pressure data and/or flow data. Forexample, pressure information may be obtained at locations before andafter the stent and at various points within the stent. This pressureinformation may be used to assess the performance of the stent and maybe used in estimates of the restenosis probability value. In someembodiments, pressure information may be used by the processing devicealong with the imaging data to generate the estimated restenosisprobability value.

At step 601, a catheter is inserted into a lumen of the vessel. This maybe done as shown in FIGS. 2A and 2B as described herein. The cathetermay include a stent placement assembly, like the balloon assembly 202 ofFIGS. 2A-F or the balloon 302 shown in FIGS. 3 and 4 as describedherein, and an intravascular ultrasound imaging device. Such as theimaging assembly 304, also of FIGS. 3 and 4. In some embodiments of themethod 600, the catheter may be inserted by manual control of thecatheter by a clinician, the catheter may be inserted using roboticcontrol at the direction of the clinician, or the catheter may beinserted using automatic robotic control wherein the catheter is steeredby the processing system 101 to the site of the lesion. For example, thecatheter may be a steerable intravascular device 114, coupled to a PIM116 that received commands from the processing system 101, or directlyfrom the bedside control 118, to steer the catheter's tip and direct thecatheter into and out of a vessel. After the catheter is positioned atthe site of a lesion within the lumen of the vessel, the stent placementassembly may be activated to place the stent at the site of the lesionwithin the lumen of the vessel, as depicted in FIG. 2C. In placing astent, the stent may be deployed such that it expands against the wallsof the lumen to improve flow within the vessel.

At step 602, intravascular ultrasound imaging data is collected usingthe intravascular ultrasound imaging device of the catheter. This may bedone while performing a pullback of the catheter, such that imaging datais obtained along the vessel from a distal side of the stent or thelesion and to a proximal side of the stent or the lesion. The imagingdata includes information about the placement of the stent at the siteof the lesion and may be processed by the processing system 101 toprovide specific information regarding tissue types, plaque presenceand/or types, and information regarding the location of the stent withinthe vessel (e.g., whether the vessel include pronounced bends, the stentdiameters on either side of the stent, etc.). For example, theinformation may include information regarding the cross-sectional areaof the vessel before and after the stent and within the stent. Thus,when the stent is not deployed having a generally circularcross-sectional area, the intravascular ultrasound imaging device mayprovide information to indicate this to the clinician. Additionally, ifgaps are present between the stent and the luminal walls in some portionof the span of the stent, the imaging data may include informationenabling the processing system 101 to interpret and analyze the gap andprovide visualization of the gap in a display in some embodiments.

At step 604, a processing device such as the CPU 104 of the processingsystem 101 may estimate a restenosis probability value based on theintravascular ultrasound imaging data of the placement of the stent atthe site of the lesion. Many algorithms may be used to process thecollected imaging data obtained at the site of the lesion and otherinformation to generate an objective measure of restenosis probability.The processing device may estimate the restenosis probability valuebased on tissue types at the site, plaque types at the site and/orplaque presence and geometry, a type of the stent, and/or the locationof the stent within the vessel, the presence of gaps between the stentand the walls of the vessel, the cross-sectional area through the stent(including the shape and/or size of the area and the uniformity of thecross-sectional area through the stent), whether the lesion extendsbeyond the stent, etc. In some embodiments, the processing device mayestimate the restenosis probability value based on the degree ofcurvature in the vessel in areas proximal to the stent. Additionally, insome embodiments the data other than imaging data may be used to provideinformation regarding the performance of the stent. For example,pressure information and/or flow information may be obtained atlocations before and after the stent and at various points within thestent. This pressure and flow information may be used to assess theperformance of the stent and may be used in estimates of the restenosisprobability value. In some embodiments, pressure information may be usedby the processing device along with the imaging data to generate theestimated restenosis probability value.

At step 606, an indication of the estimated restenosis probability valueis communicated to a clinician. For example, the processing system 101may cause an indication of the estimated restenosis probability value tobe displayed in the display 122 or in a touchscreen display of thebedside controller 118. For example, the processing system 101 may causea user interface, such as the user interface 500 to be displayed. Asshown in FIG. 5, the user interface 500 includes a stent placementinformation window 510 as described herein. The estimated restenosisprobability value 516 may be displayed in the estimated restenosisprobability area 514 is a numerical value, is a color, as text, or as acombination thereof. In some embodiments the estimated restenosisprobability value may be interpreted by the processing system 101 beforedisplay to the clinician. For example, the estimated restenosisprobability value may be compared with a plurality of brackets that mapto descriptions of estimated restenosis probability, such as “poor.”“fair.” “good, etc. In some embodiments, the indication of the estimatedrestenosis probability value may be communicated to the clinician is asound, such as a beep, a chime, or an alarm to indicate that restenosisis likely or unlikely as indicated by the imaging data and otherinformation obtained by the catheter at the site of the lesion afterplacement of the stent. Based on the estimated restenosis probability,the clinician may reinsert the stent deployment assembly within thestent and apply pressure again to deploy the stent, as shown in FIGS. 2Eand 2F. Thereafter, data may be collected, and the restenosisprobability may be calculated again to predict future stent performancein view of the redeployment.

Referring now to FIG. 7, shown therein is a flow chart of a method 700of treating a vessel within a patient. Like the method 600 of FIG. 6,the method 700 is illustrated as a plurality of steps or operations.Additional steps may be performed before, after, in between, or as partof these enumerated steps. Steps of the method 700 may be performed bythe medical system 100 of FIG. 1. An embodiment of the method 700 maybegin at step 702 in which a catheter is positioned at a site of alesion within a lumen of the vessel. The catheter includes a stentplacement assembly. At step 704, the stent placement assembly isactivated place the stent at the site of the lesion within the lumen ofthe vessel. For example, as shown in FIG. 3, the catheter may include aballoon 302 that may be deployed and the fluidic pressure to cause thestent to expand against the luminal walls of the vessel. For example,the stent may be deployed as illustrated in FIG. 4 by the stent 400.Once deployed, the stent may restore flow through the vessel.

In order to assess whether the stent is likely to provide long-term,future benefits, a restenosis probability value is estimated based onthe placement of the stent at the site of the lesion, at step 706. Therestenosis probability value may be estimated by the processing system101 of FIG. 1. For example, the CPU 104 may receive imaging data and/orother data obtained within the vessel at the placement of the stent andmay analyze the data to determine tissue types, plaque types, thelocation of the stent within the vessel including the cross-section ofthe vessel at multiple points within the stent and the degree of bendingof the vessel or adjoining vessels near the stent. Additionally, the CPU104 may receive imaging data and/or other data obtained prior to theplacement of the stent. The CPU 104 may execute algorithms and methodsstored as executable code in the instructions 112 on the memory 106. Insome embodiments of the method 700, an indication of the estimatedrestenosis probability value may be communicated to a clinician toinform the clinician that an intervention should be performed so thatlong-term future benefits of the stent may be achieved. For example, theprocessing system 101 may determine that the estimated restenosisprobability value would be increased by inserting the balloon 302 intothe stent again and re-inflating the balloon using a higher pressurethan originally employed. The processing system 101 may determine thatthe estimated restenosis probability value would be increased byinserting an ablation device within the stent and performing an ablationprocess to remove some of the plaque from the site of the lesion. Thestent may be redeployed using a higher pressure or using the samepressure after the ablation process. Upon termination of eachintervention, data may be obtained at the placement of the stent toassess and re-assess the restenosis probability by an estimationalgorithm. For example, the processing system 101 may determine from theimaging data that a stent is deployed, in at least some portion of thestent, to only a fraction, such as 65%, of its maximum diameter. Otheralgorithms may include different threshold values and may operate onmore variables extracted from the imaging data.

Referring now to FIG. 8, shown therein is a flow chart of a method 800of treating a vessel of the patient. As illustrated, the method 800includes a step 802 in which imaging data is received. The imaging datais obtained by, and received from, an imaging device on a catheter at aplacement site of a stent within a lumen of a vessel of a patient. Forexample, the processing system 101 of FIG. 1 may receive imaging dataobtained by the intravascular device 114. The imaging data may haveundergone some processing by the PIM 116 and/or the acquisition card 108prior to reception by the CPU 104 of the processing system 101. In step804, the processing system estimates the restenosis probability valuebased on the imaging data obtained by the imaging device. The estimatedrestenosis probability value may be based on the placement of the stentat the site of a lesion.

At step 806, an indication of the estimated restenosis probability valuemay be communicated to a clinician. The indication may be communicatedin many different ways as described herein. The processing system 101may send information to a display to communicate the estimatedrestenosis probability value. Thus, a numerical representation of theestimated restenosis probability value may be displayed on a displaycoupled to the processing system 101, a sound may be emitted from thespeaker of the processing system 101, etc. Additionally, in someembodiments of the method 800, and intervention recommendation may bedetermined and provided to a clinician when the stent is determined tobe under deployed, or otherwise performing unsatisfactorily, based onthe imaging data obtained by the imaging device. In some embodiments,the processing system may receive non-imaging data, such as pressuredata or other physiological data, obtained by another sensor or sensorsincluded in the catheter. The estimated restenosis probability value maybe calculated based on the non-imaging data or on a combination ofimaging data and non-imaging data.

In some embodiments, instructions for performing the operations includedin embodiments of the method 800 may be stored in a non-transitorycomputer readable medium, such as the memory 106 of the processingsystem 101. Accordingly, embodiments of the present disclosure includesystems having processing devices, such as the CPU 104 or the processingsystem 101 more generally, that perform one or more of the methods 600,700 and 800 when instructions corresponding to one or more of theenumerated steps of these methods are provided as executable code storedon the non-transitory computer readable medium.

At step 606, a processing device such as the CPU 104 of the processingsystem 101 may estimate a restenosis probability value based on theintravascular ultrasound imaging data of the placement of the stent atthe site of the lesion. Many algorithms may be used to process thecollected imaging data obtained at the site of the lesion and otherinformation to generate an objective measure of restenosis probability.The processing device may estimate the restenosis probability valuebased on tissue types at the site, plaque types at the site and/orplaque presence and geometry, a type of the stent, and/or the locationof the stent within the vessel, the presence of gaps between the stentand the walls of the vessel, the cross-sectional area through the stent(including the shape and/or size of the area and the uniformity of thecross-sectional area through the stent), whether the lesion extendsbeyond the stent, etc. In some embodiments, the processing device mayestimate the restenosis probability value based on the degree ofcurvature in the vessel in areas proximal to the stent. Additionally, insome embodiments the data other than imaging data may be used to provideinformation regarding the performance of the stent. For example,pressure information and/or flow information may be obtained atlocations before and after the stent and at various points within thestent. This pressure and flow information may be used to assess theperformance of the stent and may be used in estimates of the restenosisprobability value. In some embodiments, pressure information may be usedby the processing device along with the imaging data to generate theestimated restenosis probability value.

At step 612, an indication of the estimated restenosis probability valueis communicated to a clinician. For example, the processing system 101may cause an indication of the estimated restenosis probability value tobe displayed in the display 122 or in a touchscreen display of thebedside controller 118. For example, the processing system 101 may causea user interface, such as the user interface 500 to be displayed. Asshown in FIG. 5, the user interface 500 includes a stent placementinformation window 510 as described herein. The estimated restenosisprobability value 516 may be displayed in the estimated restenosisprobability area 514 is a numerical value, is a color, as text, or as acombination thereof. In some embodiments the estimated restenosisprobability value may be interpreted by the processing system 101 beforedisplay to the clinician. For example, the estimated restenosisprobability value may be compared with a plurality of brackets that mapto descriptions of estimated restenosis probability, such as “poor,”“fair,” “good,” etc. In some embodiments, the indication of theestimated restenosis probability value may be communicated to theclinician is a sound, such as a beep, a chime, or an alarm to indicatethat restenosis is likely or unlikely as indicated by the imaging dataand other information obtained by the catheter at the site of the lesionafter placement of the stent. Based on the estimated restenosisprobability, the clinician may reinsert the stent deployment assemblywithin the stent and apply pressure again to deploy the stent, as shownin FIGS. 2E and 2F. Thereafter, data may be collected and the restenosisprobability may be calculated again to predict future stent performancein view of the redeployment.

Referring now to FIG. 8, shown therein is a flowchart of a method 800 oftreating a vessel within a patient. Like the method 600 of FIG. 6, themethod 800 is illustrated as a plurality of steps or operations.Additional steps may be performed before, after, in between, or as partof these enumerated steps. Steps of the method 800 may be performed bythe medical system 100 of FIG. 1. An embodiment of the method 800 maybegin at step 802 in which a catheter is positioned at a site of alesion within a lumen of the vessel. The catheter includes a stentplacement assembly. At step 804, the stent placement assembly isactivated place the stent at the site of the lesion within the lumen ofthe vessel. For example, as shown in FIG. 3, the catheter may include aballoon 302 that may be deployed and the fluidic pressure to cause thestent to expand against the luminal walls of the vessel. For example,the stent may be deployed as illustrated in FIG. 4 by the stent 400.Once deployed, the stent may restore flow through the vessel.

In order to assess whether the stent is likely to provide long-term,future benefits, a restenosis probability value is estimated based onthe placement of the stent at the site of the lesion, at step 806. Therestenosis probability value may be estimated by the processing system101 of FIG. 1. For example, the CPU 104 may receive imaging data and/orother data obtained within the vessel at the placement of the stent andmay analyze the data to determine tissue types, plaque types, thelocation of the stent within the vessel including the cross-section ofthe vessel at multiple points within the stent and the degree of bendingof the vessel or adjoining vessels near the stent. Additionally, the CPU104 may receive imaging data and/or other data obtained prior to theplacement of the stent. The CPU 104 may execute algorithms and methodsstored as executable code in the instructions 112 on the memory 106. Insome embodiments of the method 800, an indication of the estimatedrestenosis probability value may be communicated to a clinician toinform the clinician that an intervention should be performed so thatlong-term future benefits of the stent may be achieved. For example, theprocessing system 101 may determine that the estimated restenosisprobability value would be increased by inserting the balloon 302 intothe stent again and re-inflating the balloon using a higher pressurethan originally employed. The processing system 101 may determine thatthe estimated restenosis probability value would be increased byinserting an ablation device within the stent and performing an ablationprocess to remove some of the plaque from the site of the lesion. Thestent may be redeployed using a higher pressure or using the samepressure after the ablation process. Upon termination of eachintervention, data may be obtained at the placement of the stent toassess and re-assess the restenosis probability by an estimationalgorithm. For example, the processing system 101 may determine from theimaging data that a stent is deployed, in at least some portion of thestent, to only a fraction, such as 65%, of its maximum diameter. Otheralgorithms may include different threshold values and may operate onmore variables extracted from the imaging data.

Referring now to FIG. 9, shown therein is a flowchart of a method 900 oftreating a vessel of the patient. As illustrated, the method 900includes a step 902 in which imaging data is received. The imaging datais obtained by, and received from, an imaging device on a catheter at aplacement site of a stent within a lumen of a vessel of a patient. Forexample, the processing system 101 of FIG. 1 may receive imaging dataobtained by the intravascular device 114. The imaging data may haveundergone some processing by the PIM 116 and/or the acquisition card 108prior to reception by the CPU 104 of the processing system 101. In step904, the processing system estimates the restenosis probability valuebased on the imaging data obtained by the imaging device. The estimatedrestenosis probability value may be based on the placement of the stentat the site of a lesion.

At step 906, an indication of the estimated restenosis probability valuemay be communicated to a clinician. The indication may be communicatedin many different ways as described herein. The processing system 101may send information to a display to communicate the estimatedrestenosis probability value. Thus, a numerical representation of theestimated restenosis probability value may be displayed on a displaycoupled to the processing system 101, a sound may be emitted from thespeaker of the processing system 101, etc. Additionally, in someembodiments of the method 900, and intervention recommendation may bedetermined and provided to a clinician when the stent is determined tobe underdeployed, or otherwise performing unsatisfactorily, based on theimaging data obtained by the imaging device. In some embodiments, theprocessing system may receive non-imaging data, such as pressure data orother physiological data, obtained by another sensor or sensors includedin the catheter. The estimated restenosis probability value may becalculated based on the non-imaging data or on a combination of imagingdata and non-imaging data.

In some embodiments, instructions for performing the operations includedin embodiments of the method 900 may be stored in a non-transitorycomputer readable medium, such as the memory 106 of the processingsystem 101. Accordingly, embodiments of the present disclosure includesystems having processing devices, such as the CPU 104 or the processingsystem 101 more generally, that perform one or more of the methods 600,800, and 900 when instructions corresponding to one or more of theenumerated steps of these methods are provided as executable code storedon the non-transitory computer readable medium.

Embodiments of the present disclosure provide for the assessment ofstents after deployment within a vessel. By using data obtained withinthe vessel, including data obtained within the stent itself, aprobability of restenosis may be estimated based on objectiveinformation obtained from the data. Using the objective information,such as imaging data, the processing system may provide an objectiveindication of current and/or future stent performance. Additionally, theprocessing system may recommend one or more interventions to improve thecurrent and/or future performance of the stent. By assessing andimproving the placement of the stent at the time of placement, one ormore future interventions may be avoided. Avoiding unnecessaryinterventions is beneficial to both patients and clinicians.

What is claimed is:
 1. A method of treating a vessel within a patient,the method comprising: positioning a catheter at a site of a lesionwithin a lumen of the vessel, the catheter comprising a stent placementassembly; providing treatment of the vessel by activating the stentplacement assembly to place the stent at the site of the lesion withinthe lumen of the vessel; determining, using a processing device incommunication with an intravascular ultrasound (IVUS) imaging transducerpositioned within the vessel, whether there is a probability ofrestenosis, wherein determining whether there is the probability ofrestenosis comprises: controlling the IVUS imaging transducer to emitultrasound waves and receive echoes associated with the ultrasoundwaves; obtaining IVUS imaging data of the stent at the site of thelesion based on the received echoes; processing the IVUS imaging data tocompute a diameter of the vessel and a deployed size of the stent; andcomparing the computed deployed size of the stent to the computeddiameter of the vessel; and communicating, via a display coupled to theprocessing device, a notification indicating that there is theprobability of restenosis to a clinician in response to determining thatthere is the probability of restenosis.
 2. The method of claim 1,wherein obtaining the IVUS imaging data comprises using the IVUS imagingtransducer to obtain the IVUS imaging data as the IVUS imagingtransducer is pulled back through the vessel.
 3. The method of claim 2,wherein the IVUS imaging data comprises tissue information.
 4. Themethod of claim 1, wherein determining whether there is the probabilityof restenosis further comprises determining at least one of: a tissuetype at the site; plaque presence at the site; a type of the stent; thesite of the stent within the vessel; or a performance of the stent,wherein the performance is based on at least one of: pressuremeasurements; or flow measurements.
 5. The method of claim 1, furthercomprising wherein comparing the computed deployed size of the stent tothe computed diameter of the vessel comprises computing a relativedeployed size of the stent, and wherein determining whether there is theprobability of restenosis comprises determining whether the relativedeployed size of the stent exceeds a threshold value.
 6. The method ofclaim 5, wherein the notification comprises at least one of a visualnotification or an audio notification.
 7. The method of claim 1, whereindetermining whether there is the probability of restenosis comprisesdetecting underdeployment of the stent at the site of the lesion.
 8. Themethod of claim 7, further comprising providing, via the display, arecommendation, to the clinician, to address the underdeployment of thestent at the site of the lesion by redeploying the stent.
 9. The methodof claim 7, further comprising providing, via the display, arecommendation, to the clinician, to address the underdeployment of thestent by an ablation process.
 10. The method of claim 1, whereinprocessing the IVUS imaging data to compute the deployed size of thestent comprises computing a cross-sectional area of the stent, andwherein determining whether there is the probability of restenosiscomprises determining whether there is the probability of restenosisbased on the cross-sectional area of the stent.
 11. A medical diagnosisand treatment system, comprising: a non-transitory computer-readablemedium to store instructions thereon; and a processing device incommunication with the medium and an intravascular ultrasound (IVUS)imaging catheter, wherein the processing device is configured to executethe instructions to perform operations comprising: receiving IVUSimaging data obtained by the IVUS imaging catheter at a placement siteof a stent within a lumen of a vessel of a patient, the placement sitecorresponding to a location of a lesion of the vessel; computing adiameter of the vessel and a deployed size of the stent based on thereceived IVUS imaging data of the stent within the lumen of the vessel;comparing the computed deployed size of the stent to the computeddiameter of the vessel; and determining whether there is a probabilityof restenosis based on the comparison of the deployed size of the stentto the computed diameter of the vessel; and sending, to a displaycoupled to the processing device, information communicating whetherthere is the probability of restenosis to an operator of the medicaldiagnosis and treatment system.
 12. The medical diagnosis and treatmentsystem of claim 11, further comprising the display.
 13. The medicaldiagnosis and treatment system of claim 11, wherein the operationsfurther comprise: determining whether the stent is underdeployed; andsending, to the display, an intervention recommendation when the stentis determined to be underdeployed.
 14. The medical diagnosis andtreatment system of claim 11, wherein determining whether there is theprobability of restenosis further comprises receiving non-imaging dataobtained by a non-imaging sensor of the catheter, the non-imaging datarepresentative of at least one of pressure or flow of blood within thevessel.
 15. The system of claim 11, wherein the informationcommunicating whether there is the probability of restenosis comprisesat least one of a quantitative description or a qualitative description.16. The system of claim 11, wherein the processing device is configuredto perform the operation comprising computing the deployed size of thestent by computing a diameter of the stent, wherein the diameter of thevessel comprises at least one of the diameter adjacent to the lesion,the diameter proximal to the lesion, or the diameter distal to thelesion; or wherein the diameter of the stent comprises at least one of aproximal end diameter or a distal end diameter.